Composite material inlay in additively manufactured structures

ABSTRACT

Techniques for inlaying a composite material within a tooling shell are disclosed. In one aspect, an additively manufactured tooling shell is provided, into which a composite material is inlaid and cured. A surface of the tooling shell is provided with indentations or another mechanism to enable adherence between the composite material and the tooling shell. The resulting integrated structure is used as a component in a transport structure.

CROSS-REFERENCE TO RELATED APPLICATION(S

The present Application is a Divisional of U.S. Non-Provisionalapplication Ser. No. 15/730,675, filed Oct. 11, 2017, entitled“COMPOSITE MATERIAL INLAY IN ADDITIVELY MANUFACTURED STRUCTURES” whichis expressly incorporated by reference herein in its entirety.

BACKGROUND Field

The present disclosure relates generally to manufacturing techniques,and more specifically to 3-D printed components for use in vehicles,boats, aircraft and other transport structures.

Background

Numerous types of components are manufactured and used in transportstructures such as vehicles, trucks, trains, motorcycles, boats,aircraft, and the like. Such components may include both “off the shelf”and customized components that can serve any one or more of functional,structural or aesthetic purposes within, or as part of, a transportstructure.

Many types of such components constitute a generally rigid structuralmember composed of metal, an alloy, a polymer, or another suitablematerial. The structural member may have a predefined shape and mayinclude one or more surfaces, indentations, or cavities that aremanufactured to adhere to separate layers of a suitably molded compositematerial. For example, part of an interior door panel in a vehicle mayinclude a metal or plastic structure inlaid with carbon fiber reinforcedpolymer (CRFP). In this example, the CRFP layer may be included to addstrength and durability to the panel while maintaining a comparativelylightweight and aesthetically-pleasing design. Many other types ofcomposite materials may be used, depending on factors like the type oftransport structure and the nature and intended use of the part.

Machining the tooling shells used to mold the layers of compositematerial into the desired shape for use with such a structure is, moreoften than not, an expensive and time-consuming process. In conventionalproduction techniques, a tool for molding the composite material istypically manufactured using labor-intensive processes. For example, amachining process may be used to manufacture a pair of tooling shellswhich may each constitute one of a positive and a negative section of amold. Materials and resin may be placed in the mold between the positiveand negative tooling shell sections to thereby shape a structure. Thetooling shells, in turn, are typically composed of one or more materialsthat are chemically and structurally suitable for use in molding thesubject materials. Often such structures have properties that make themdifficult to accurately cut into the desired mold shape or form detailedfeatures.

After the molding of the composite layers is complete, the toolingshells may have limited or no further uses beyond the scope of use toform that single type of part. Further, the structure in which themolded material is to be inlaid may have to be separately fabricatedusing an unrelated technique, potentially rendering the manufacturingprocess even more expensive and laborious.

SUMMARY

Composite material inlaid with additively manufactured tooling shellswill be described more fully hereinafter with reference tothree-dimensional printing techniques.

One aspect of a method of manufacturing a part for a transport structureincludes three-dimensional (3-D) printing a tooling shell, the toolingshell including a surface configured to adhere to a material, applyingthe material to the surface using the tooling shell as part of a mold,and forming an integrated structure including the tooling shell and thematerial, the integrated structure for assembly as a component in thetransport structure.

Another aspect of a method of manufacturing a part for a transportstructure includes three-dimensional (3-D) printing a tooling shell, andproducing an integrated structure including the tooling shell and amaterial applied to a surface of the tooling shell, the integratedstructure for use as the part in the transport structure, the producingthe integrated structure further including using the tooling shell tomold the composite material, and securing the composite material to thetooling shell.

It will be understood that other aspects of methods of producing partsfor transport structures will become readily apparent to those skilledin the art from the following detailed description, wherein it is shownand described only several embodiments by way of illustration. As willbe realized by those skilled in the art, the parts and methods ofproducing the parts are capable of other and different embodiments andits several details are capable of modification in various otherrespects, all without departing from the invention. Accordingly, thedrawings and detailed description are to be regarded as illustrative innature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

Composite material inlaid with additively manufactured tooling shellswill now be presented in the detailed description by way of example, andnot by way of limitation, in the accompanying drawings, wherein:

FIG. 1 is a flow diagram illustrating an exemplary process of initiatinga process of 3-D printing.

FIG. 2 is a block diagram of an exemplary 3-D printer.

FIG. 3 shows a perspective view of a 3-D printed tooling shell

FIG. 4 shows a perspective view of 3-D printed tooling shell with CFRPinserted therein.

FIG. 5 is a cross sectional perspective view of the combined materialand tooling shell.

FIG. 6 shows a side view of an exemplary interior door panel 610 in atransport structure using the dual assembled component.

FIG. 7 is a flow diagram illustrating an exemplary process for producinga component having a composite reinforcement overlaying a tooling shellto form an integrated structure for use as a component in a transportstructure.

FIG. 8 is an illustration of an integrated structure composed of anoverlay of fabric composite reinforcement over additively manufacturedtooling.

FIG. 9 is an illustration of an integrated structure including toolingformed with an internal lattice structure.

FIG. 10 is an illustration of the integrated structure having pocketsand tooling with topology optimization.

FIG. 11 is an illustration of an integrated structure using co-moldednodes.

FIG. 12 is a flow diagram illustrating an exemplary process forproducing a component having a composite material over a tooling shellto produce an integrated structure for use as a component in a transportstructure.

FIG. 13 is an illustration of an integrated structure includingcomposite material sandwiched between nodes and fastened via amechanical clamp.

FIGS. 14A-B are an example of an integrated structure using a compositeskin and multi-material tools.

FIG. 15 is an example of an integrated structure using peel plies on thecured composite surface.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended to provide a description of various exemplaryembodiments of techniques for fabric composite reinforcement overadditively manufactured tooling and is not intended to represent theonly embodiments in which the invention may be practiced. The term“exemplary” used throughout this disclosure means “serving as anexample, instance, or illustration,” and should not necessarily beconstrued as preferred or advantageous over other embodiments presentedin this disclosure. The detailed description includes specific detailsfor the purpose of providing a thorough and complete disclosure thatfully conveys the scope of the invention to those skilled in the art.However, the invention may be practiced without these specific details.In some instances, well-known structures and components may be shown inblock diagram form, or omitted entirely, in order to avoid obscuring thevarious concepts presented throughout this disclosure.

The use of additive manufacturing, also known as 3-D printing, in thecontext of composite tooling provides significant flexibility forenabling manufacturers of mechanical structures and mechanizedassemblies to manufacture parts with complex geometries. For example,3-D printing techniques provide manufacturers with the flexibility todesign and build parts having intricate internal lattice structuresand/or profiles that are not possible to manufacture via traditionalmanufacturing processes.

FIG. 1 is a flow diagram 100 illustrating an exemplary process ofinitiating a process of 3-D printing. A data model of the desired 3-Dobject to be printed is rendered (step 110). A data model is a virtualdesign of the 3-D object. Thus, the data model may reflect thegeometrical and structural features of the 3-D object, as well as itsmaterial composition. The data model may be created using a variety ofmethods, including 3D scanning, 3D modeling software, photogrammetrysoftware, and camera imaging.

3D scanning methods for creating the data model may also use a varietyof techniques for generating a 3-D model. These techniques may include,for example, time-of flight, volumetric scanning, structured light,modulated light, laser scanning, triangulation, and the like.

3-D modeling software, in turn, may include one of numerous commerciallyavailable 3-D modeling software applications. Data models may berendered using a suitable computer-aided design (CAD) package, forexample in an STL format. STL files are one example of a file formatassociated with commercially available CAD software. A CAD program maybe used to create the data model of the 3-D object as an STL file.Thereupon, the STL file may undergo a process whereby errors in the fileare identified and resolved.

Following error resolution, the data model can be “sliced” by a softwareapplication known as a slicer to thereby produce a set of instructionsfor 3-D printing the object, with the instructions being compatible andassociated with the particular 3-D printing technology to be utilized(step 120). Numerous slicer programs are commercially available. Slicerprograms convert the data model into a series of individual layersrepresenting thin slices (e.g., 100 microns thick) of the object beprinted, along with a file containing the printer-specific instructionsfor 3-D printing these successive individual layers to produce an actual3-D printed representation of the data model.

A common type of file used for this purpose is a G-code file, which is anumerical control programming language that includes instructions for3-D printing the object. The G-code file, or other file constituting theinstructions, is uploaded to the 3-D printer (step 130). Because thefile containing these instructions is typically configured to beoperable with a specific 3-D printing process, it will be appreciatedthat many formats of the instruction file are possible depending on the3-D printing technology used.

In addition to the printing instructions that dictate what and how anobject is to be rendered, the appropriate physical materials necessaryfor use by the 3-D printer in rendering the object are loaded into the3-D printer using any of several conventional and often printer-specificmethods (step 140). In fused deposition modelling (FDM) 3-D printers,for example, materials are often loaded as filaments on spools, whichare placed on one or more spool holders. The filaments are typically fedinto an extruder apparatus which, in operation, heats the filament intoa melted form before ejecting the material onto a build plate or othersubstrate, as further explained below. In selective laser sintering(SLS) printing and other methods, the materials may be loaded as powdersinto chambers that feed the powder to a build platform. Depending on the3-D printer, other techniques for loading printing materials may beused.

The respective data slices of the 3-D object are then printed based onthe provided instructions using the material(s) (step 150). In 3-Dprinters that use laser sintering, a laser scans a powder bed and meltsthe powder together where structure is desired, and avoids scanningareas where the sliced data indicates that nothing is to be printed.This process may be repeated thousands of times until the desiredstructure is formed, after which the printed part is removed from afabricator. In fused deposition modelling, parts are printed by applyingsuccessive layers of model and support materials to a substrate. Ingeneral, any suitable 3-D printing technology may be employed forpurposes of this disclosure.

FIG. 2 is a block diagram of an exemplary 3-D printer 200. While anynumber of 3-D printed technologies can be suitably employed, the 3-Dprinter 200 of FIG. 2 is discussed in the context of an FDM technique.3-D printer 200 includes an FDM head 210 which in turn includesextrusion nozzles 250A and 250B, a moveable build stage 220, and a buildplate 230 at the top of the build stage 220.

Depending on the intended composition of the structure and the need forany support material for providing support to overhanging elements ofthe structure that might otherwise be subject to possible gravitationaldeformation or collapse, a plurality of materials may be used forprinting an object. One or more suitable filament materials 260 may bewound on a spool (not shown) and fed into FDM head 210. (In othertechnologies described above, the material may be provided as a powderor in other forms). The FDM head 210 can be moved in X-Y directionsbased on the received printing instructions by a numerically controlledmechanism such as a stepper motor or servo motor. The material, whichmay in one exemplary embodiment constitute a thermoplastic polymer, maybe fed to the FDM head 210 which includes the extrusion nozzles 250A and250B. The extruder in FDM head 210 heats the filament material 260 intoa molten form, and extrusion nozzle 250 a ejects the molten material anddeposits it onto the build plate 230 of build stage 220.

Responsive to the received printing instructions, the FDM head 210 movesabout a horizontal (X-Y) plane such that extrusion nozzle 250A drops thematerial 260 at the target location to form a line 240 of appliedmaterial. (The FDM head 210 may also be configured to move in theZ-direction and/or to rotate about one or more axes in certainconfigurations). The layer 270 of material 260, including line 240, isformed by depositing the material 260 line by line, with each line ofthe material 260 hardening as the material is deposited on the buildplate 230. After one layer 270 is formed at the appropriate locations inthe X-Y plane, the next layer may be formed in a similar way.

The build plate 230 may be a component of a controlled table moveable inat least the vertical Z direction. When rendering of a layer 270 iscompleted, the build stage 220 and build plate 230 may lower by anamount proportional to the thickness of layer 270 in the vertical (Z)direction so that the printer can begin application of the next layer,and so on until a plurality of cross sectional layers 240 having adesired shape and composition are created.

While a substantially rectangular structure of layers is shown forpurposes of simplicity in this illustration, it will be appreciated thatthe actual printed structure may embody substantially any shape andconfiguration depending on the data model. That is, the actual shape ofthe rendered layers will correspond to the defined geometry of the3D-model being printed.

In addition, as indicated above, a plurality of different materials maybe used to print the object. In some instances, two different materials260 and 280 may concurrently be applied by respective extruder nozzles250A and 250B.

In an exemplary embodiment, a part for a transport structure is formedusing an appropriately shaped and structured tooling shell to mold oneor more layers of composite material. The composite material is adheredto the surface of the tooling shell to form an integrated structure thatincludes both the composite material and the tooling shell. Theintegrated structure is operable for use as a component in a transportstructure such as a vehicle. In an exemplary embodiment, the toolingshell is 3-D printed, thereby eliminating the often costly andtime-consuming techniques associated with the laborious machiningprocess. In these embodiments, the tooling shell may play the dual roleof molding the composite material and serving as a useful structure inconjunction with the molded material to form a component for assemblywithin the transport structure itself, such as a vehicle panel, joint orother component, an aircraft wing, and the like.

FIG. 3 shows a perspective view of a 3-D printed tooling shell 300. Thetooling shell may include any material having appropriate or suitablecharacteristics for molding another material. For example, if thematerial to be molded using the tooling shell is carbon fiber reinforcedpolymer (CFRP), then an Invar alloy may be a suitable candidate for usein molding the material because its coefficient of thermal expansion isvery similar to that of carbon fiber. In other cases, the toolingstructure may composed of other materials, including metals, alloys andplastics. The indentation 302 in tooling shell 300 may be of a suitablevolume for accommodating an appropriate amount of material to be molded.In another exemplary embodiment, an upper half of a tooling shell may beprovided in order to seal the material during curing. In still otherembodiments, vacuum and fluid channels may be integrated into toolingshell 300 in order to enable resin material to be provided toindentation 302 to facilitate the process of fabricating the material.In other embodiments, because the tooling shell 300 may ultimately serveas a structural part in addition to a mold, the choice of materials outof which tooling shell 300 can be made may also be limited by the typesof materials that are appropriate for the final component as assembledinto the transport structure.

In one embodiment, the adhesive to be used for CRFP and the metal 3-Dprinted mold can be the matrix material of the CFRP itself.

Further included in FIG. 3 are small surface indentations 304 that hadbeen 3-D printed into the material. Because the tooling shell 302 andthe material to be molded can ultimately form a single component forassembly into a transport structure, it may be desirable in someembodiments to provide a mechanism to cause the component to adhere tothe interior 302 of the tooling shell 300. The purpose of the smallsurface indentations 304 are to assist in providing surface adhesionbetween the inner portion of tooling shell 300 and the material to bemolded in tooling shell 300. In other embodiments, surface indentationsmay also be formed on the inner side walls 306 of the tooling shell tofurther facilitate the surface adhesion process. In alternativeembodiments, other means may be used to assist in surface adhesion. Forexample, a resin may be applied to inner surface 302 prior to insertionof the materials to be molded. Alternatively, clamps, screws, nuts andbolts, nails, thermal fusion, etc. may be used to secure the compositematerial to the tooling shell.

FIG. 4 shows a perspective view of 3-D printed tooling shell 400 withCFRP inserted therein. As noted above, a geometry 404 of a structure tobe molded within the tooling shell 400 may be designed to conform to theshape of an inner surface of the tooling shell 400, depending on how themold is configured. In this manner, the tooling shell acts as a sectionof a mold to shape the composite material that will be cured into the aportion of the component, as described further below.

A composite fabrication process including a composite layup may beperformed using the tooling shell 400. In this example, carbon fibermaterial (or another suitable material) may be applied via a layupprocess on inner surface of the tooling shell 400 as a first step inproducing the component. The carbon fiber material may be laid over thetooling shell 400, compressed and cured.

FIG. 5 is a cross sectional perspective view 500 of the combinedmaterial 502 and tooling shell 504. The difference in shading betweenmaterial 502 and tooling shell 504 shows that the two structures in thisparticular embodiment have a different material composition, althoughsuch a feature need not be necessary in certain embodiments.

FIG. 6 shows a side view of an exemplary interior door panel 610 in atransport structure using the dual assembled component 600. In thisembodiment, the door panel includes a first component 606 and a secondcomponent 608, either of which may be molded or 3-D printed. In thisexemplary embodiment, first component 606 is adhered via any availablemeans to a surface 607 of the component 600 described in FIGS. 3-5.Second component 608 is adhered via any available means to a surface 609of the component of FIG. 4 (i.e., the unseen bottom portion of thecomponent in FIG. 4). The interior panel 610 can thereupon be used in atransport structure with the carbon fiber material 604 appropriatelyplaced. It should be understood that the integration of the componentwith an interior door panel is purely for illustrative purposes, and thecomponent of FIG. 4 can be used in a wide number of practicalapplications in various portions of a transport structure.

In one exemplary embodiment, a layup uses pre-impregnated (“prepreg”)carbon fiber plies that are delivered onto the tooling shell 400 (FIG.4) with the resin matrix applied. The prepreg technique provideseffective resin penetration and assists in ensuring substantiallyuniform dispersion of the resin. The prepreg plies may be applied ontothe tooling shell 400 to form a laminate stack.

In another embodiment, a dry lay-up uses dry woven fiber sheets. Resinmay thereupon be applied to the dry plies after layup is complete, suchas by resin infusion. In an alternative exemplary embodiment, wet layupmay be used wherein each ply may be coated with resin and compactedafter being placed.

As indicated above, a top shell or a seal for the mold may be 3-Dprinted and applied over tooling shell 400 to provide a means to moldthe structure 502 (FIG. 5), for example, into the geometry 404 of theinner part of the tooling shell 400 (FIG. 4). Upon completion of themolding process, the carbon fiber material may, for example, be vacuumcompacted and baked in an oven for a designated time period.

The specific molding and resin infusion processes used during thesestages may vary depending on variables such as molding techniques,design constraints, and desired manufacturing yield. Generally, the3-D-printed tooling shell may be used in connection with a variety ofcomposite manufacturing techniques including, for example, ResinTransfer Molding (RTM), hand layup, prepregs, sheet molding, and VacuumAssisted Resin Transfer Molding (VARTM).

FIG. 7 shows an exemplary flow diagram of a method for creating acomponent for use in a transport structure. At 702, a tooling shell is3-D printed using a geometry that can ultimately enable it to be used aspart of an integrated structure for further within another structuresuch as a vehicle panel. The tooling shell may be designed for potentialadherence to a material to be subsequently used. At 704, the material,such as CFRP or another composite fabric, is applied and a compositefabrication process is used to mold and harden the material. At 706,when the composite fabrication is complete, the material adheres to thetooling shell and a resulting component is formed which includes anintegrated structure composed of the cured material and the toolingshell. At 708, the integrated structure is assembled as a component intoa transport structure.

In another exemplary embodiment, a 3-D printed plastic frame is firstused as a template for composite tooling. On completion of the cure ofthe composite material, the resulting assembly may then be used as aframe or other component for a transport structure. FIG. 8 is anillustration of a structure composed of an overlay of fabric compositereinforcement over additively manufactured tooling. The 3-D printingtechnology selection may be driven by the materials requirement and bythe speed of the printing process. A 3-D printed plastic frame 802 isformed. Advantageously, plastic printing processes are typically 25-50times faster than metal printing processes. A further benefit in usingadditively manufactured plastic tooling is the ability to obtain largerparts because the build chambers of plastic 3-D printers are typicallymuch larger than those of metal 3-D printers. Additionally, the plastic3-D printers can in many cases print much smoother surfaces. In anembodiment, the material used is Acrylonitrile Butadiene Styrene (ABS),a common thermoplastic polymer. However, any number of suitablematerials may be used depending on the application and the properties ofthe materials needed.

Further, in the embodiment shown, a CNC foam core 806 is additivelymanufactured and coupled to plastic frame 802 using an adhesive or otheravailable means. In one embodiment, the frame 802 and core 806 areco-printed in a single rendering. The foam core may be composed of thesame material as plastic frame 802. In another embodiment, a honeycombpanel configuration is used in place of foam core. It will beappreciated that the illustrated embodiment in FIG. 8 is exemplary innature as a number of materials and shapes may alternatively be used forpurposes of this disclosure.

A variety of fiber composite fabrics may be used in the subsequentcomposite fabrication process, depending on strength requirements andother factors. Some examples of possible materials include glass fiber,carbon fiber, Kevlar, and the like. In the embodiment shown, glass fiberprepregs 804 are draped over the additively manufactured tooling. Theglass fiber pregreg layer 804 may include, in one exemplary embodiment,a fiber reinforced polymer (FRP) skin (E Glass). Other composites,including carbon fiber, may be used as well. Layup is performed on theFRP. After the material is cured, the integrated structure composed ofthe ABS tooling with frame 802 and foam core 806 and the overlaid glassfiber composite 804 may then be used as a component in a transportstructure.

For added weight savings and/or for improved load bearing capabilities,depending on the application and intended use of the integratedstructure, the 3-D printed tooling may include a structure that uses anoptimized topology. FIG. 9 shows an illustration of an integratedstructure including tooling formed with an internal lattice structure.Plastic tooling 902 includes a lattice structure designed for the loadsto which it will be subject when it is assembled as a component. Thefoam core or honeycomb panel structure 906 is included, with the layersof glass fiber reinforced polymer 904 overlaid on the tooling structure.One advantage of this structure includes the savings in plastic materialachieved via use of the lattice.

In another exemplary embodiment, the tooling may be additivelymanufactured with pockets for a flush finish. FIG. 10 is an illustrationwith the integrated structure having pockets and tooling with topologyoptimization. As seen in FIG. 10, tooling component 1002 is 3-D printedwith pockets 1007, 1009 and hollow sections 1008. The pocket 1007enables the end areas of the glass fiber material surrounding thetooling to have a flush finish. The structure further includes acomponent 1006 with a honeycomb or foam filling. In addition, to providereinforcement of one of the pockets 1007, 1009 where mechanicalreinforcement is desirable or necessary, CFRP or another compositematerial may be used to provide local reinforcement for the pockets. Asbefore, prepreg layers of GFRP (or another suitable composite) may beoverlaid and cured over the tooling to produce the integrated structure.

In some embodiments, mechanical clamping may be desirable to secure thecomposite materials in place. FIG. 11 is an illustration of anintegrated structure using co-molded nodes. As in previous embodiments,tooling shell 1102 is additively manufactured using ABS or anothersuitable material. FRP or another suitable material 1104 is inlaid andcured over the tooling shell. A 3-D printed inner node 1114 isco-printed with the tooling or printed separately and added to secure afirst side of portions 1120 of the composite material 1104. Likewise, a3-D printed outer node 1112 is inserted over a second side of portions1120 of the composite material. The composite material is thereforeclamped and secured to the tooling shell, and the entire integratedstructure may be used as a component in a transport structure. In oneexemplary embodiment, the nodes are co-printed using aluminum to ensurestrength. Other materials, however, may be equally suitable.

In an exemplary embodiment, AM metal nodes can be implemented assuspension pick-up points or interfaces for the crush rails associatedwith the overall transport structure. Crush rails are energy absorbingrail structures that may be implemented on a vehicle to enable thevehicle to absorb energy from an impact in a controlled and directedmanner. The rails may be sandwiched between the metal nodes, which inturn may be attached to the vehicle suspension. An example of such anarrangement is shown in FIG. 13. In another embodiment, mechanicalclamping can be used in connection with vacuum connectors to cure acomposite layup.

FIG. 13 is an illustration of an integrated structure 1300 includingcomposite material sandwiched between nodes and fastened via amechanical clamp. The structure 1300 includes upper and lower aluminumnodes 1302 a-b, which may be additively manufactured. Beneath node 1302b is tooling shell 1308, which may be additively manufactured using FDMor another suitable technology. In an embodiment, tooling shell 1308 iscomposed of ABS or a thermoplastic such as ULTEM (polyetherimide).

Laid over tooling shell 1308 are two composite skin layers 1306 a and1306 b which may be composed of GFRP. Near their end, GFRP layers 1306 aand 1306 b contact with nodes 1302 a-b. GFRP layers 1306 a and 1306 bmay be cured on top of both of the AL node 1302 b and the FDM toolingshell 1308. GFRP layers 1306 a-b may then be clamped by nodes 1302 a,which may be placed on top of GFRP layers 1306 a and 1306 b.

To secure the clamping of layers 1306 a and 1306 b, a feature 1304 formechanical fastening may be employed. The feature 1304 in thisembodiment is a large opening in which a bolt or other fastener can beinserted. The fastener can provide a force to secure the layers 1306 aand b, such as by using a standard threaded bolt, a nut-bolt combinationor any other suitable mechanical fastening or clamping mechanism. Inother embodiments, the clamping feature may be different than theaperture 1304 and may include other types of fasteners or openings toaccommodate fasteners.

Also shown in FIG. 13 is a protrusion 1310 from the node 1302 b. Theprotrusion includes an aperture that is configured to “snap fit” intoanother protrusion 1312, which may be a protrusion from the FDM toolingshell 1308. In an embodiment, the protrusion 1312 is a gradualprotrusion jutting out of a longer FDM member (hidden from view by node1320 b) arranged in the vertical direction, with the larger protrusion1312 at the end. The AL node 1302 b may contact and press against thelonger FDM member. As the AL node 1302 b is moved downward relative tothe longer FDM member, the pressure or force causes the larger FDMprotrusion 1312 to snap into place. In an embodiment, protrusion 1312may be affixed to a vehicle suspension system, thereby fasteningstructure 1300 to the suspension system. These techniques enable thealuminum clamping mechanism to interface with the FDM tool.

FIG. 12 is a flow diagram illustrating an exemplary process forproducing a component having a composite material over a tooling shellto produce an integrated structure for use as a component in a transportstructure. At 1202, a plastic tooling shell such as an ABS shell isadditively manufactured using a suitable 3-D printer, such as an FDM 3-Dprinter. Thereupon, at 1204, a foam core or honeycomb panel is 3-Dprinted, and aluminum nodes are also 3-D printed. In one embodiment, ofthe three structures additively manufactured in collective steps 1202,1204, two or more of the structures are co-printed. It should be notedthat different materials may be used than the materials identified,depending on the embodiment and objectives.

At 1206, the tooling shell is coupled to or adjoined with the foam core.In some embodiments where the two components are additively manufacturedas a single unit, this step may be unnecessary. In other embodiments, anappropriate adhesive, screw, clamp or other connection means may beused.

At 1208, the appropriate material, such as GFRP, is inlaid over thetooling shell and is prepared and cured in a composite fabricationprocess. In some embodiments, the tooling shell and foam core have anadhesive means to adhere to the composite. In other embodiments, otheradherence mechanisms may be used. At 1210, for example, the aluminumnodes printed at 1204 may be used to clamp the composite material to thetooling shell in a manner described above with respect to FIG. 11.

Thereupon, at 1212, the resulting integrated structure may be used as acomponent in a transport structure. In some embodiments discussed above,the structure may use a lattice or other mechanical arrangement, such asa CFRP layer, to provide additional support depending on the stresses towhich the structure may be subject. The tooling shell can be optimizedand printed with pockets for placing additional reinforcement whereneeded. In an embodiment, GFRP is overlaid with the tooling structure,but CFRP is used in pockets on the tooling shell to optimize load pathfor load transfer. These configurations may also enable use ofunidirectional reinforcement in the pockets/features on the toolingshell as well as woven reinforcement (unidirectional has fibers in onedirection while woven has fibers running in the 0 and 90 degree angles).In transport structures and other wheeled vehicles, load transfer is thechange of load sustained by the different wheels during the processes oflongitudinal and lateral acceleration, which includes braking anddeceleration. Other types of loads may also be involved in transportstructures and mechanized assemblies. A shear load is a force thatcauses shear stress when applied to a structural element. Reinforcementusing composite fiber materials, lattices, and other structures may benecessary in cases where load the transfer mechanics of a part,including the expected shear loads, dictates it.

In other embodiments, multi-material tools may be used. For example,certain sections of the tooling may be printed with a dissolvablematerial. Once the composite is overlaid and cured, these sections maybe dissolved. This technique may be ideal for weight saving mechanismsand in designs where only the composite shell is needed. In the casewhere only composite skin is needed in a certain section, multi-materialtools may be used. In an embodiment, release mechanisms (release agents,tooling surface preparation, etc.) may be used to enable certainsections of the tooling to come out or become available after thecomposite has cured to achieve sections with just composite skin.

FIGS. 14A-B are an example of an integrated structure 1400 using acomposite skin and multi-material tools. Referring to FIG. 14A, amulti-material tooling shell including components 1404 and 1406 may beadditively manufactured. Here, unlike component 1404 which may be anordinary thermoplastic or other suitable material rendered using FDM (orin some cases it may be a metallic material rendered using some other AMtechnology), component 1406 may constitute a known dissolvable material.A skin or material 1402 such as GFRP or CFRP is laid up over the toolingshell as discussed above. It is desired that the final integratedstructure include components 1404 and 1402. However, component 1406 isused merely for molding purposes to shape and stabilize material 1402and to allow it to cure. Accordingly after material 1402 is cured,component 1406 may be dissolved away using techniques conventionallyknown to produce the final integrated structure 1400 in FIG. 14b . Usingthese multi-material techniques in conjunction with the methodsdisclosed herein, an increasingly wide variety of structures may beproduced.

In another aspect of the disclosure, peel plies can be disposed on thesurface of the cured composite to improve adhesive bonding. FIG. 15 isan example of an integrated structure 1500 including a composite 1514such as GFRP, CFRP, or the like. As in prior embodiments, an additivelymanufactured tool 1516 is used to mold the composite 1514 during a layupprocess as well as to be a part of the structure being built. To improvethe bonding between the cured composite 1514 and the 3-D Printed tool1516, a layer of a material with chemically suitable properties, such aspeel ply 1512, can be arranged between the tool 1516 and the composite1514. To enable an accurate result in some embodiments, another layer ofpeel ply 1512 may be inserted over the composite 1514. Between the upperpeel ply layer 1512 and a bagging film 1508 is breather 1510. Baggingfilm 1508 may include thru-bag vacuum connector for creating negativepressure. Sealant 1502 may be used to seal the bagging film 1508, and aflash tape 1504 may be used to secure the peel ply 1512 to the composite1514.

On completion of the cure, the nature of the peel ply 1512 enables thecured composite 1514 to be removed from the tool 1516. The peel ply 1512may leave a certain texture on the surface of the cured composite 1514that is conducive to adhesive bonding. After discarding the peel ply1512, adhesive can be applied between the tool-composite interface tothereby form a strong bond between the tool 1516 and composite 1514.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these exemplary embodiments presented throughout thisdisclosure will be readily apparent to those skilled in the art, and theconcepts disclosed herein may be applied to other techniques forcomposite inlay of materials. Thus, the claims are not intended to belimited to the exemplary embodiments presented throughout thedisclosure, but are to be accorded the full scope consistent with thelanguage claims. All structural and functional equivalents to theelements of the exemplary embodiments described throughout thisdisclosure that are known or later come to be known to those of ordinaryskill in the art are intended to be encompassed by the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims. No claim element is to be construed under the provisions of 35U.S.C. § 112(f), or analogous law in applicable jurisdictions, unlessthe element is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited using the phrase “stepfor.”

What is claimed is:
 1. An apparatus comprising: a three-dimensional(3-D) printed tooling shell; and an integrated structure including acomposite material formed with the tooling shell, wherein the compositematerial is secured to the tooling shell.
 2. The apparatus of claim 1,wherein the integrated structure is operable for assembly into atransport structure.
 3. The apparatus of claim 1, wherein the compositematerial includes a carbon fiber reinforced polymer.
 4. The apparatus ofclaim 1, wherein the integrated structure further includes a compositematrix material with adhesive properties.
 5. The apparatus of claim 1,wherein the 3-D printed tooling shell includes coarse sections on asurface to increase adhesion with the composite material.
 6. Theapparatus of claim 1, wherein the 3-D printed tooling shell includes acavity.
 7. The apparatus of claim 1, wherein the composite material isformed of inlaid carbon fiber.
 8. The apparatus of claim 1, wherein thecomposite material is formed using a composite fabrication process.
 9. Amethod of manufacturing a component for a transport structure,comprising: three-dimensional (3-D) printing a tooling shell; andproducing an integrated structure comprising: molding a compositematerial using the tooling shell; and securing the composite material tothe tooling shell.
 10. The method of claim 9, wherein the integratedstructure is operable for assembly into the transport structure.
 11. Themethod of claim 9, wherein the composite material comprises carbon fiberreinforced polymer.
 12. The method of claim 9, wherein the producing anintegrated structure further comprises applying a composite matrixmaterial having adhesive properties.
 13. The method of claim 9, whereinthe 3-D printing the tooling shell comprises printing coarse sections onthe surface to increase adhesion with the composite material.
 14. Themethod of claim 9, wherein the 3-D printing the tooling shell comprisesforming a cavity in the tooling shell within which the surface islocated.
 15. The method of claim 9, wherein the applying the materialonto the surface comprises inlaying carbon fiber within the cavity. 16.The method of claim 9, wherein the producing an integrated structurecomprises applying the composite material using a composite fabricationprocess.